In an idle mode of an IEEE (Institute of Electrical and Electronics Engineers) 802.16e system, paging is performed in a unit of paging group. A mobile station can belong to a plurality of paging groups, and a paging controller of each paging group performs paging of the mobile station if call or user packet of an external network occurs. At this time, the paging controller transfers a paging message to all base stations within a paging group, and the base stations which have received the paging message broadcast a paging advertisement message MOB_PAG-ADV to the mobile station.
FIG. 1 is a diagram illustrating a procedure of performing paging in an idle mode of the IEEE 802.16e system.
A mobile station receives a deregistration command message MOB_DREG-CMD from a base station when entering an idle mode. The mobile station identifies a paging cycle, paging offset, paging listening interval of a paging information field of the deregistration command message DREG-CMD. Then, the mobile station monitors a channel by using the identified paging cycle, paging offset, and paging listening interval, so as to receive a paging message transferred thereto.
According to the related art, a problem occurs in that the mobile station should monitor the paging message by continuously turning on a radio channel for a paging listening interval of maximum 5 OFDMA frames (25 ms) if the paging message is not transferred to the mobile station.